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Pulminary Blood Flow and Control of Regulation
Terms and things to know
47
Physiology
Graduate
01/13/2011

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Cards

Term
A patient blows into a spirometer as hard and fast as possible. You notice that the FEV1 of the patient is only 1.1L, about 30% of their FVC.  This patient could have...
Definition
Obstructive pulmonary disease (Emphysema)
Term

 

A patient blows into a spirometer as hard and fast as possible.  You notice that although the FEV1 of the patient is 87% of their FVC, the total volume of air expired (FVC) is about 3L.  You suspect that the patient has...

 

Definition
Restrictive pulmonary disease (Fibrosis)
Term
How does pulmonary circulation keep resistance low even in the face of an increased CO (as in exercise)?
Definition
Additional capillary channels are opened, increasing the number of parallel vessels and thus lowering resistance.
Term
These vessels bring and take blood from alveolar vessels.  They become compressed with expiration.
Definition
Extra alveolar vessels.
Term
These vessels deal with blood delivery/removal from alveoli.  They are compressed with inspiration.
Definition
alveolar capillaries.
Term
Why is the oxygen tension of blood in the left atrium slightly lower than the oxygen tension of blood in the early pulmonary veins?
Definition
Bronchiole veins empty into the pulmonary veins, slightly mixing in deoxygenated blood (PvO2=40mmHg) with oxygenated blood (PvO2=100mmHg).
Term
Which extravascular force in the lung help keep extra alveolar vessels open at high lung volumes?
Definition
radial traction on the extra alveolar vessels.
Term

In the top of the lung (zone 1) which vessel has the highest pressure?

 

A)Pa

B)Pv

C)PA

Definition
C. PA
Term

In the middle of the lung (zone 2) which vessel has the highest pressure?

 

A)Pa

B)Pv

C)PA

Definition
A)Pa
Term

In the bottom of the lung (zone 3) which vessel has the lowest pressure?

 

A)Pa

B)Pv

C)PA

Definition
C) PA
Term
What does FIO2 stand for and what is its normal value?
Definition
Fraction of Oxygen in the atmosphere. 21%
Term

What does PIO2 stand for and what is its normal value?

Definition
Partial pressure of inspired oxygen.  150mmHg
Term

What does PAO2 stand for and what is its normal value?

Definition
Partial pressure of oxygen in the alveoli.  100mmHg
Term

 

What does PaO2 stand for and what is its normal value?

 

Definition
Partial pressure of oxygen in the pulmonary veins.  90mmHg
Term

 

 

What does PvO2 stand for and what is its normal value?

 

 

Definition
Partial pressure of oxygen in pulmonary arteries.  40mmHg.
Term

 

What does PaCO2 stand for and what is its normal value?

 

Definition
Partial pressure of carbon dioxide in pulmonary arteries. 40mmHg.
Term

 

What does PvCO2 stand for and what is its normal value?

 

Definition
partial pressure of oxygen in the pulmonary veins. 46mmHg
Term

 

What does CaO2 stand for and what is its normal value?

 

Definition
The content of oxygen in the blood as a volume.  20.6ml O2/100ml blood.
Term

How can one calculate the PIO2 in an individual?

 

How can this be used to calculate PAO2?

Definition

PIO2=(PB-PH2O)xFIO2  normally 150mmHg

 

PAO2=PIO2-PCO2  normally 100mmHg

Term
Is oxygen or CO2 more soluble in the alveoli?  How is this difference made up?
Definition

CO2.  O2 has a larger pressure driving force:

PAO2-PvO2=100mmHg-40mmHg=60mmHg

PvCO2-PACO2=46mmHg-40mmHg=6mmHg

Term
When the membrane of the alveoli is the restriction for a substance's diffusion into the blood, this is a...
Definition
diffusion limited substance (e.g. is carbon monoxide)
Term
When the flow of blood is the limiting factor to a substance's entry into the bloodstream, this is called...
Definition
A perfusion limited substance (e.g. is nitric oxide)
Term
Why are O2 partial pressure changes more drastic than CO2 changes in a person with a diffusion impairment?
Definition
higher than normal CO2 levels induce hyperventilation to blow off extra CO2 while O2 does not have this effect in and of itself.
Term

A decreased V/Q ratio indicates what type of pulmonary disease?

 

How does this occur?

Definition

Obstructive pulmonary disease (emphysema).

 

Ventilation ceases, lowering PAO2 and raising PACO2 slightly.  Thus, ventilation decreases while flow remains unchanged.

Term

an increased V/Q ratio indicates what kind of pulmonary disease?

 

How does this occur?

Definition

A restrictive pulmonary disease (fibrosis).

 

PAO2 increases, but PCO2 becomes 0 because there is little to no perfusion.  Thus, V/Q approaches infinity.

Term
How is it that the top of the lung has a higher V/Q ratio than the bottom of the lung?
Definition
Ventilation decreases as you ascend along the lung, but perfusion decreases even more.
Term
A brain trauma patient becomes hypoxic.  What is a likely cause?
Definition
hypoventilation (causes pCO2 to increase)
Term

A patient suffering from pulmonary edema suffers from hypoxemia.  What is the cause?

 

What would this person's PACO2 value be?

Definition
Impaired diffusion.  PACO2 will probably be 40mmHg if not extremely severe and with hyperventilation.
Term
A patient is suffering from tachypnea.  is it safe to assume that they are hypoxic?
Definition
No.  Measure pCO2 via a pulse oximeter.
Term
A young infant is cyanotic and has a high breathing rate.  What is a possible cause?
Definition
anatomic shunt (patent foramen ovale)
Term
A chronic smoker suffers from hypoxia.  what is a possible cause?
Definition
Ventilation- perfusion inequality due to emphysema 
Term
What would the PO2, blood saturation level and blood oxygen content levels in a patient do in anemia?
Definition

PO2=nothing

SAT=nothing

Content=reduced (less Hb)

Term

What would the PO2, blood saturation level and blood oxygen content levels in a patient do in CO poisoning?

Definition

PO2=nothing

SAT=go down (CO competition for Hb)

Content=go down (less free Hb)

Term

What would the PO2, blood saturation level and blood oxygen content levels in a patient that lives in the mountains of Colorado?

Definition

PO2=go down (FIO2 is reduced at high altitude)

SAT=go down (Less available O2)

Content=go down slightly, but return to normal (more Hb would be made with chronic hypoxia)

Term
What factors induce Hb release of O2?
Definition

Temperature,

dropped pH

Increased CO2 levels

Increased BPG levels

Term
How is most CO2 transported in the bloodstream?
Definition
Transported as carbonic acid (90% arteriolar, 60% venous)
Term
Decreased O2 levels and increased CO2 levels in an arteriole does what to arteriolar capillaries surrounding it?
Definition
vasoconstriction.
Term
why does pulmonary artery pressure increase in patients with emphysema?
Definition
Large portions of the capillary bed are destroyed, decreasing the number of available parallel vessels to decrease resistance.  Also, widespread hypoxia induces constriction of the alveolar capillaries.  Hypoxia also induces polycythemia, increasing blood viscosity.  Lastly, radial traction is lost, keeping lung volume chronically high and the arteriolar vessels compressed even more.
Term
Why is there a small tendency for fluid leakage into the lung interstitium?
Definition
higher than normal interstitial oncotic pressure just out paces capillary hydraulic pressure, causing net filtration.  Keeping alveoli free from this fluid via lymphatics is key to maintaining this oncotic pressure.
Term
What can cause pulmonary edema?
Definition

increased capillary hydrostatic pressure (heart failure, MI, etc.)

increased capillary permiability

decreased lymph drainage

decreased interstitial oncotic pressure (causes fluid to leak directly into alveoli).

Term
Which spinal nerves give rise to the phrenic nerve?
Definition
C3, 4 and 5
Term
Which brain stem section is responsible for the quality of a respiratory breath (breath is on time and proper inspiration/expiration depth)
Definition
Pneumotaxic center
Term
Which brain stem section is responsible for maintaining the proper breathing rate?
Definition
Apneustic center
Term
Which brain stem section is responsible for the actual initiation of breathing?
Definition
Medullary center
Term
When are the dorsal nerve groups most actively firing?  What other nerve group that is attached to the glossopharyngeal and vagus nerves is associated with this the dorsal nerve group?
Definition

Initiating inhalation.

 

Nucleus of the tractus solitarius.

Term
These lung receptors sense interstitial pressure.
Definition
J receptors
Term
Why can't the chemosensitive regions of the brain stem detect O2 levels like the carotid chemoreceptors?
Definition
O2 cannot directly cross the blood brain barrier while CO2 can.
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